sudomod

ICs:
-TPS60190RSAR - Boost converter
-MCP73871 - LiPo charger
-ATMEGA32U4 x 2 - Arduino compatible microcontroller
-LM3671MF (5V --> 3V3) - LDO regulator
-PCM2704C - USB sound card
-MAX98306 - Stereo audio amp
-FE1.1s - USB hub
-TXB0108 - Level shifter

TODO:
-Add voltage divider to battery so arduino can measure voltage

I've got a PCB that's close to ready to be fab'd, but I want to be sure it'll be functional before I do that.

How it works:
TPS61090 boosts LiPo voltage to 5.2 volts for the entire system. Works alongside MCP73871 which charges battery. This is the powerboost portion. I have two ATMEGAs because I need both USB functionality and a lot of pins. One is almost entirely dedicated to the lower display while the other handles buttons. They communicate over I2C. The LM3671 takes 5V and converts it to 3.3 for the level shifter. The bottom display's logic runs at 3.3 volts, so it needs to be connected to the 5 volt arduino through the TXB0108 level shifter. The PCM2704C is a full USB DAC and the MAX98306 is a 3.7 watt stereo amp. The FE1.1s is the USB hub connecting the arduinos, sound card and an external USB port.

I've got a full BOM but still need a physical way to control volume. I was thinking about hooking the PCM2704C into one of the arduinos and having it be controlled on screen, but then there's an unused bit on the DS case.

This is my first complex board, so I'm sure I've made a mistake somewhere. I'd appreciate any feedback, especially if you've used these chips before. The schematic is attached to this post. Once it's done, I'll release the board files.

P.S - I've taken some schematics directly from Adafruit. I know the designs work and I've been using them on breadboards for testing.

Why do you need a voltage divider for the battery monitor? Arduino can handle 0-5v on analog pins. To measure voltage you have to hookup before the step up converter.

Also do you mind putting a description in the OP next to the ic list, ex. Ic977 - op amp

I don't need a voltage divider. I'm not sure why I thought I did. I've not touched this for a while, but I'm reconsidering having all the circuits implemented on the board. It would be much easier to design a "hub" to which separately purchasable boards can be soldered. It saves soldering effort and is actually cheaper for one-off boards.